Pac-Nor and Lothar-Walther and Sharp shooters supply offer pre fit barrel all you do is screw on and head space.
I'm not sure what your looking to do or spend but I personaly would have the ation barreled like the Rem 700 and do away with the barrel nut.
I have actualy had realy good luch with using the factory Savage heavy barrels (1-9) and rechambering them to
22-250Ai to shoot the 69gr SMK bullets. They all shoot pretty well accuracy wise and after a few hundred rounds they don't foul to bad either. You migh find one used and shoot it to see how it does or shoot a Tubbs final finish kit through it then have it cut back and rechambered with a good reamer.
